1. I was delighted to learn that the Ambrosian Church and the Order of Friars Preachers are preparing to celebrate the 750th anniversary of the martyrdom of St Peter Martyr, a Dominican religious who, with his colleague Fra Dominic, was killed for the faith on 6 April 1252, the Saturday after Easter, near Seveso, while travelling to Milan to take up a new mission of evangelization and defence of the Catholic faith.

The anniversary, which this year too coincides with the Saturday after Easter, is an incentive to look with admiration and gratitude at the figure and work of this saint who, seized by Christ, fulfilled in his life the words of the Apostle Paul: "Woe to me if I do not preach the Gospel!" (I Cor 9,16), and, with his martyrdom, obtained the grace of full conformity with the paschal Victim.

On this special, happy occasion, I rejoice with the Archdiocese of Milan that benefited from his zealous activity, promoted his canonization, preserves his mortal remains and the place of his martyrdom. I cordially unite with the Sons of St Dominic who in him honour their first martyr, an exceptional model for consecrated persons and for the Christians of our time.

2. St Peter Martyr lived his whole life under the banner of the defence of the truth, expressed in the Apostles' "Creed", which he was in the habit of reciting from the age of seven, although he had been born into a family infiltrated by the Cathar heresy, and continued to proclaim "until his final moment" (cf. Bullarium Romanum, III, Augustae taurinorum, 1858, p. 564). The Catholic faith that he had learned in childhood saved him from the dangers of the university atmosphere of Bologna, where going to pursue his studies, he met St Dominic and became his fervent disciple, spending the rest of his life in the Order of Friars Preachers.

After his ordination, he exercised his apostolic activity in various cities of northern Italy, Tuscany, Romagna, the Ancona region of the Marches and Rome itself, primarily through the ministry of preaching and reconciliation. As prior of the convents at Asti, Piacenza and Como, he extended his pastoral care to cloistered women religious, for whom he founded the Dominican monastery, St Peter's in Campo Santo, Milan.

To counter the harm caused by heresy, he took great pains with the Christian formation of lay people and in the capitals of Lombardy and Tuscany, he promoted the associations whose aim was to defend orthodoxy, to spread the devotion to the Blessed Virgin Mary and perform the works of mercy. He later formed a deep spiritual friendship with the Seven Holy Founders of the Servants of Mary, and became their invaluable advisor.

3. On 13 June 1251, while he was prior in Como, my venerable Predecessor Innocent IV gave him a special mandate to oppose the Cathari heresy in Cremona and the following autumn appointed him inquisitor for the cities of Milan and Como and the surrounding regions.

The holy martyr began his last mission that would lead him to die for the Catholic faith. In carrying out the important office, he intensified his preaching, proclaiming the Gospel of Christ and explaining the sound doctrine of the Church, while he did not pay attention to the repeated death threats he received from many sides.

His missionary zeal and obedience often took him into the see of St Ambrose, where he expounded the mysteries of Christianity to great crowds and engaged in many public disputes with the leaders of the heretical Cathar sect. His preaching, nourished by a sound knowledge of Scripture, was combined by an ardent witness of charity and confirmed by miracles. Everywhere with unflagging apostolic activity he inspired spiritual zeal fostering a genuine renewal of Christian life.

Unfortunately, on 6 April 1252, while he was on his way from Como where he had celebrated Easter with his community, to Milan where he was going to undertake the mandate entrusted to him by the Vicar of Christ, he was killed by an assassin, hired by the heretics, who at Seveso, in the Farga region, struck him in the head with a sickle and stabbed his companion. This town subsequently took the martyr's name and there one can visit the shrine and parish dedicated to him.

4. St Catherine of Siena notes that with his martyrdom, the heart of this outstanding defender of the faith, burning with divine love, continued to release "light in the darkness of the many heresies". His assassin, Carino da Balsamo, whom he forgave, was converted and later put on the Dominican habit. Remarkable was the widespread, intense feeling provoked by his brutal assassination. Not only did the echo spread through the Dominican Order and the Diocese of Milan but also throughout Italy and Christian Europe. The Milanese authorities, summing up the unanimous veneration of the martyr, asked Pope Innocent IV to canonize him. The canonization took place in Perugia in March 1253, a little less than a year after his death. In the Bull with which he was added to the list of martyrs, my venerable Predecessor praised his "devotion, humility, obedience, goodness, piety, patience and charity", and presented him as a "fervent lover of the faith, its outstanding champion and even fervent protector".

Through the Dominican Order, the devotion honouring St Peter Martyr spread rapidly among the Christian people, as many works of art attest which call forth his undaunted faith, and his martyrdom. A special witness of his enduring devotion is offered by the Shrine of Seveso and the Basilica of St Eustorgius in Milan where since 7 April 1252 the mortal remains of this glorious martyr have been venerated.

Pope St Pius V wished to dedicate a beautifully decorated chapel to him in the Pian Tower, that is part of the Vatican Museums. There my saintly Predecessor often celebrated the Eucharistic sacrifice. Since 1818, St Peter Martyr has accompanied and supported the formation of Ambrosian seminarians with his heavenly protection, for in that year, a diocesan seminary community took up residence in the ancient friary of Seveso next to the Shrine that commemorates his martyrdom.

Antidote to partial, lukewarm faith and to gap between Gospel and life, Gospel and society 5. Seven hundred and fifty years after his death, St Peter Martyr, a faithful disciple of the supreme Teacher whom he constantly sought in silence and contemplation, tirelessly proclaimed and loved to the point of the supreme gift of his life, urges the Christians of our time to overcome the temptation of a lukewarm, partial, adherence to the faith of the Church. He invites us all to focus with renewed commitment on Christ "to be known, loved and imitated, so that we may live the life of the Trinity, and with him transform history until its fulfilment in the heavenly Jerusalem" (Novo Millennio ineunte, n. 29). St Peter holds up and presents to believers the path of holiness, "the high standard of ordinary Christian living", so that the ecclesial community, individuals and families may always be led in this direction (cf. ibid., n. 31). After his example, every Christian is encouraged to resist the allure of power and riches, to seek first "his kingdom and its justice" (Mt 6,33) and to contribute to the building of a social order that corresponds more and more closely to what is needed to respect the dignity of the human person.

In a society like ours where there is often a worrisome gap between Gospel and culture, a recurrent tragedy in the history of the Christian world, St Peter Martyr witnesses that this gap can only be bridged if the different members of the People of God strive to become "lamps" that shine on their stand, guiding their brethren to Christ, who gives ultimate meaning to human seeking and expectations.

I express the wish that the celebrations planned in honour of this exemplary son of St Dominic may be an occasion of grace, spiritual fervour and renewed commitment to announcing the Gospel with fearless courage and joy constantly renewed.

With these hopes, I impart the desired Apostolic Blessing to you, Venerable Brother, to the beloved Archdiocese of Milan, to those training for the priesthood at the seminary named after the holy martyr, to the Order of Preachers, and to all who entrust themselves to the heavenly intercession of St Peter Martyr.